Clamping connector



3, 1950 M. M. SILVERMAN CLAMPING CONNECTOR INVENTOR Filed July 25, 1.945

mill/I 41 MONTE M. SlLVERM/AN ATTORNEY Patented May 23, 1950 CLAMPIN GCONNECTOR Monte M. Silverman, Los Angeles, Calif., assignor' to T & MManufacturing Company, Los Angeles, Calif.,

a firmcomposed of Thomas and J. J. Masterson Michael Application July23, 1945, Serial No. 606,664

4 Claims. 1

This invention relates to improvements in clamping connectors forelectric cabinet boxes such as switch boxes, gutter" boxes and the like.

The objects of the invention are to provide a connector for metalcabinet boxes which is simple 7 in construction; which is easily appliedthus making possible a saving in time; which rigidly holds together twoor more boxes or affords rigid support for one or more boxes on another;which provides a conduit through which the electric wires may be quicklyand'easily passed without injury to the insulation; which provides goodelectrical connection between the members clamped together therebyaffording a good ground circuit. I

These and other objects are attained by my invention, which will beclearly understood from the following description and the accompanyingdrawing in which:

Fig. 1 is a cross-sectional view showing my clamping connector as usedto clamp together the adjoining walls of swtch boxes and the like;

Fig. 2 is an end elevational view of the sleeve member of my device;

Fig. 3 is an end elevation of the assembled clamping connector;

Fig. 4 is an end elevational view of the spacer member of my device;

Fig. 5 is a side elevation of the spacer member;

Fig. 6 is an enlarged fragmentary view of a portion of the spacermember;

Fig. 7 is a cross-sectional view taken on the line l-'l of Fig. 6;

Fig. 8 is an end view of a modification of the sleeve member;

Fig. 9 is an enlarged fragmentary edge view of a tooth of Fig. 8.

In connection with electric wiring practice, it is often desirable touse two or more metal cabinet boxes positioned close together, and toconnect these two boxes with each other mechanically by means which willform a conduit through which electrical conductors or wires may passfrom one box to the other. It has been common practice to use externallythreaded pipe nipples and nuts, or internally threaded bushings toconnect two boxes together in this manner. These require not only moreexpensive parts, but also require much more time to properly install,and the arrangement is mechanically not very rigid, and as ordinarilyapplied, the electrical connection between the parts is not good enoughto provide a satisfactory grounding circuit.

My connector may be made of strong parts, and because of the clampingaction, afiords means for 2 rigidly connecting and supporting one box onanother, for example a, switch box may be supported on a gutter box, andmay be used without further support or attachment. Referring to thedrawings, my clamping nector consists of a sleeve I0, a'spacer II and alock nut l2. As shown in Fig; 1 two partition walls of switch boxes orthe like, (represented by broken lines) are engaged, at knock-cu discholes, between the flange [3 of the" sleeve land the lock nut E2 on thethreads IE3 at the-end 0f the'sleeve opposite the flange l3, with thespacer member l i intermediate the partition walls being joined. Theelectrical wires (not shown) are passed through the cylindrical openingof the sleeve, the sharp edges having been removed to avoid abrasion oithe insulation on the wire.

The sleeve it consists of a cylindrical body having an outside flange i3with ears M which may be grasped by thefinger or engaged by a suitabletool. The under side. of the flange I3 is relieved or undercut so thatthe edges of the ears I l make good physical and electrical contact withthe metal wall, the ears being purposely sharp edged so that they willscariiy and cut through the paint or lacquer finish on the partitionwalls. The sleeve Ill is provided at the end opposite the flange withexternal thread [5, upon which the lock nut l2 may be threadedlyengaged, the lock nut l2 also being dished or relieved so that its earsI6 will scarify and cut into the surface of the partition walls beingclamped by the device.

The spacer member H is a cylindrical body loosely fitting over theoutside of the sleeve l0. adapted to space apart the partition walls ofthe switch boxes, etc. In order to make good mechanical and electricalcontact, the sleeve I0 is provided on both ends with staked scarifyingears I! with extended abutting portion HA (see Figs. 4 to 7) which aresharp edged and adapted to scarify and cut into the finish and metal ofthe partition walls, to make good electrical contact, and also toprevent loosening of the clamping device by vibration, etc. A pluralityof staked ears are formed on each end of the spacer.

As shown in Figs. 8 and 9, the ears it of the flange i3 of the sleeve itmay be slightly twisted or canted to form a leading edge I9A which isbetter adapted to scarify the paint or lacquer finish on the metal wallsof the switch boxes, etc., and to form a vibration-proof contact withthe surface. The ears of the locking nut may also be slightly canted togive better scarifying action on the metal surface to be clamped.

the bushing by the ears while tightening the nut on the assembly withhis other hand, or by means of a suitable tool applied to the nut. Inother types of connectors between boxes, it frequently requires twoworkmen, because one man cannot see to manipulate the necessary toolssimultaneously in the two boxes. When the ears of the flange are cantedto better scariiy the metal sure face, the application of a tool to thesleeve may not be required.

My device is simple and inexpensive to manufacture and to install. Theparts may, of course, be made of any suitable length and diameter tomeet. the requirements for standard electrical wiring fixtures. Theparts are preferably made of heavy stock so that rigid mechanicalconnections between boxes may he made I V I-claim: a

'1. A clamping connector. for.- electrical switch boxes and the likeconsisting or a sleeve having an outwardly extending flange atone endand external threads at the other end, the said flange having spacedperipheral scarifying ears adapted for? hand gripping and said flangehaving its sur-- face adjacent the ontersur face of the sleeve relievedto permit direct contact of said ears, with a metal wall to be clampedthereagainst; a cy linidrical-sspacer adapted to fit over said sleeve,the endsof said spacer having staked scariiying ears; and a locking nutadapted to screw onto the threads of said sleeve, said locking nuthaving scarifyingears and havinga relieved surface between its threaded.hole and said ears on the side of said nut adfiacent said spacer.

2. A clamping connector for electrical switch boxes and the likeconsisting of a sleeve having an outwardly extending flange at one endand external threads at the other end, the said flange having spacedperipheral ears, said ears being canted and adapted to scarify' a'metalwall to be clamped thereagainst; a {cylindrical spacer adapted to fitover said sleeve, the ends of said spacer having staked scarifying ears;and a locknut adapted to screw onto the threads of said sleeve, saidlocking nut having scarifying ears.

3. A clamping connector ,for electrical switch boxes and the like,consisting of a sleeve having an outwardly extending flange at one endand external threads at the other end, the said flange be n pmtvidedwith canted peripheral ears; a

cylindrical spacer adapted to flt over said sleeve,

REFERENCES, metric The toilet ns r i ree s are. it e r n. e le. of is;atent UNITED STATES PATENTS;

Number Name Date "756,246 Apr. 5, i904 850,242- Olson Mar. 1 2', 1%321,955,106 Von Normann Apr; 1'7; 19-34

